Gessieli Possebom

Use of Safety Components to Avoid Accidents With Agricultural Tractors in Public Roads

The market of agricultural tractors has an important role in the Brazilian economy, as well as the role the tractor plays in agricultural operations. With the rising level of mechanization, the traffic of tractors on public roads consequently increased, thus raising the propensity of occurring accidents. In transit, tractors present low traveling speed, besides being wider machines in comparison to cars, besides also presenting low visibility to the other drivers who use the roads. The relevance of studies that point the problems related to this type of traffic accident is related to its severity, in order to seek preventive measures. In this context, this study aimed to address the interface of safety components related to lighting and signaling with the avoidance of accidents involving agricultural tractors on public roads. This way, studies show aspects such as: the road speed limit, as well as its type and width; the number of vehicles and agricultural machinery in circulation; safety components; lighting and signaling items, influence and help to draw a characterization of accidents involving farm machinery. Among the types of accidents, collision and overturning are the most common. Even if the number of accidents with tractors is lower in relation to automotive vehicles, the severity of the accidents is greater, with propensity of 5 to 8 times more deaths. Therefore, the correct use of safety components and items of lighting and signaling on tractors, in addition to the compliance with laws and regulations, may contribute to reducing the number of accidents with agricultural machines on public roads.

Luehea divaricata Martius et Zuccarini Is a Sensitive Species to Aluminum, Not Presenting Phytoremediation Potential

The aim of this work was to evaluate the effect of different concentrations of aluminum (Al) on physiological and biochemical parameters of Luehea divaricata seedlings grown in a hydroponic system under greenhouse conditions to verify the possible tolerance to Al or phytoremediation potential of this species. Seeds of Luehea divaricata were placed to germinate in commercial substrate and after 30 days the seedlings were transferred to a hydroponic system with a complete nutrient solution, pH at 4.5±0.1, with daily adjustment. After 20 days of acclimatization, homogenous plants were selected and transferred to a new nutrient solution (without phosphorus (P) and pH at 4.5±0.1) with different concentrations of Al: 0, 25, 50, 75 and 100 mg L -1 , each treatment being composed of 10 replicates of one plant each. The experiment was conducted in a completely randomized design. After seven days of exposure to the treatments, plants were collected for physiological and biochemical analyzes. Aluminum promoted a significant reduction in fresh and dry weight of roots, stems and leaves; in plant height; leaf number; leaf area; and pigment content. On the other hand, Al promoted an increase in lipid peroxidation and guaiacol peroxidase enzyme activity. Therefore, the presence of Al in the growth medium, for the studied conditions, altered significantly both physiological and biochemical parameters in Luehea divaricata seedlings, presenting a sensitive behavior to this element. Due to these characteristics, the studied species does not show phytoremediation potential.